摘要
通过向高灰熔点淮南煤灰中添加不同质量分数的镁基助熔剂,研究镁基助熔剂对高灰熔点煤灰熔融特性的影响及其机理.结果表明:对于淮南煤灰,镁基助熔剂的理想添加质量分数为5%,能使煤灰熔点降低到1 350℃以下;通过XRD分析和SEM验证得知,耐熔矿物质莫来石是导致淮南煤灰熔点较高的原因;Mg2+与莫来石发生反应,生成了堇青石和尖晶橄榄石等易熔矿物质,导致灰熔点降低;通过研究莫来石的稳定性推断出,作为电子给予体的Mg2+易于从活性较大的O(7)和O(13)进入莫来石晶体,造成化学稳定性较弱的Al(1)—O(13)和Al(8)—O(13)共价键的断裂,引起硅酸盐网络中2个Si原子之间的距离增大,促使莫来石晶体晶格重组.
The effect of magnesium-based flux on the fusibility behavior of Huainan coal ash with high fu- sion point was studied by adding different amount of magnesium-based flux to the coal ash. Results show that for Huainan coal ash, the ideal addition is 5%, in which case the coal ash fusion point may be reduced to 1 350 ℃; the high fusion point of Huainan coal ash is found to be caused by the refractory mineral mul- lite by XRD and SEM analysis~ which may be reduced by Mg2＋ reacting with mullite to form eutectic min- erals, such as cordierite and Ringwoodite, etc. Through quantum chemical calculation, the mullite system is proved to be completely stable, and the Mg2＋ could easily enter into mullite crystals from the unsaturat- ed 0（7） and O（13）, which results in both the rupture of the covalent bond between A1（1）-O（13） and A1（8）-O（13）, and the distance enlargement between two Si atoms in silicate, and finally leads to the lat- tice recombination of mullite.
出处
《动力工程学报》
CAS
CSCD
北大核心
2015年第1期19-24,共6页
Journal of Chinese Society of Power Engineering
基金
科技部支撑计划资助项目(2012BAA12B02)
科技部国际科技合作计划资助项目(2010DFA72730)
国家自然科学基金资助项目(51176114)
关键词
镁基助熔剂
高灰熔点煤
X射线衍射
量子化学
莫来石
magnesium-based flux
coal with high ash fusion point
X-ray diffraction
quantum chemistry
mullite
